Hi sir,
JEE main result is not declared yet by CBSE board. It will soon be declared today. Just you have stay updated with us. You must go to official site of CBSE JEE MAIN 2018 for the result update.
This rank is an expected Rank. He is eligible for JEE advanced test 2018 if he score this rank. Admission in Mechanical branch can not be determined by rank it all depends upon cut off of NIT's , IIIT's , other government colleges. But he can get admission in Top Private college. Thus everything depends upon Closing rank and Cut off for that particular branch.

You should Keep checking the official site for result

The link is here http://www.jeemain.nic.in

To predict about your college based on your Rank kindly click this link https://engineering.careers360.com/jee-main-college-predictor

All the best